a Includes pickup trucks, vans, minivans, and sport utility vehicles.
b In 1994, operators and riders were counted as helmeted if wearing any type of helmet. In 1996 and 1998, only those operators and riders wearing safety helmets that met U.S. Department of Transportation (DOT) standardswere counted. Those safety helmets that do not meet DOT standards were treated as if the operator/riderwere not wearing a helmet.

NOTE: Occupants of commercial and emergency vehicles are excluded.

SOURCE: U.S. Department of Transportation, National Highway Traffic Safety Administration, Research Note,
Observed Safety Belt Use in 1999, (Washington, DC: September 1999), Internet site
http://www.nhtsa.dot.gov/people/ncsa/98obbelt.html as of April 6, 2000, table 3. Data are from the National
Occupant Protection Use Survey (NOPUS), Moving Traffic Study, 1994, 1996, and 1998.